Digital I/O

cancel
Showing results for 
Search instead for 
Did you mean: 

Generation/Acquisition using multiple HSDIO PXI 6556 with bi-directional signals

Hi,

 

I would like to run vectors to test some ICs using multiple (three) PXI6556 cards. The vectors have multiple (>20) bi-directional signals.

 

Questions:

1. The NI Examples library shows multiple-device generation and acquisition VIs. However, it seems the examples are on single direction signals. Could you show me some example on how to configure bi-directional signals?

2. The pin mapping in the vectors are not in the same order as the HSDIO card pin mapping. Is there an easy way or any tool to help channel mapping? I have 10+ vectors with 90+ digital signals. Manually remapping them is quite tedious.

3. Since we have three PXI6556 cards in the tester, is the "Multi-Device dynamic generation and acquisition" example VI the one to follow? Just to double check if there is any better way to do the configuration.

 

Thank you for your help!

Jing

0 Kudos
Message 1 of 4
(6,171 Views)

hello jcao,

 

I have adressed your questions individually below:

 

1. bi-directional examples can be found in two locations Hardware Input and Output >> Modular Instruments >> Demos >> Dynamic Acquisition and Generation Demo.vi and Hardware Input and Output >> Modular Instruments >> Dynamic Acquisition and Generation >> Stimulus and Response Load from HWS File.vi . Both of these examples utilize the bi-directional functionality of our HSDIO cards.

 

2. The easiest way to map the pins is to use the Digital Waveform Editor software. You can import a VCD (Value Change Dump) file and save it as a NI-HWS file to be imported and used in LabVIEW (the second example above will show you how to use the HWS file). A VCD file should allow you to specify a signal name and assign it to a particular line.

 

3. The  "Multi-Device dynamic generation and acquisition" example VI is the best to follow for syncing across multiple HSDIO devices. The examples use TCLK which is the recomended syncing method. I have also provided a link explaining TClk a little more thoroughly.

 

http://www.ni.com/white-paper/3675/en/

 

Applications/Systems/Test
National Instruments | AWR Group
0 Kudos
Message 2 of 4
(6,134 Views)

Hi we are trying to do almost the same thing (only using the 6555 card instead of the 6556 card).

 

We have one card by itself doing the stimulus / response correctly.

 

We repeat the same VI blocks on one page to the 2nd card (and split the signals up using the Digital Waveform Editor into two HWS files, one for the first card, and one for the second card), and use the Tclk VI blocks to set up the synchronization.

 

We are able to run this now with zero errors in the VI blocks, and it records the pattern acquisition on both cards but, the pattern generation never goes out, so the device does not respond as expected.

 

One problem our LabVIEW guy noted is that some of the VI blocks had to be in the same thread ... do we need to encapsulate ALL of the vi blocks for both cards into one LabVIEW thread?

 

0 Kudos
Message 3 of 4
(5,133 Views)

Hi Ed,

When you asked, "Do we need to encapsulate ALL of the vi blocks for both cards into one LabVIEW thread?", what are you referring to as a thread? Are you starting with the examples outlined in the above post, using similar methods for synchronization?

Regards,

Rick C.
0 Kudos
Message 4 of 4
(5,117 Views)